Investigate surface properties (molecular) of elastin and modified elastin, and to relate those properties to the material's interaction with serum components, and study the effect that such interactions have on clotting. Preparation of pure elastin and enzymatically or mechanically altered elastin for screening for thrombogenicity. Reconstitution of alpha-elastin into something approximating the original elastin structure. Characterization of the elastin surface on a molecular level, i.e., functional groups, hydrophobic patches, etc. Investigation of adsorption of a variety of proteins to the elastin surface. Evaluate the elastin surface in terms of thrombogenicity and clotting activity.